The present invention relates to a friction false-twisting unit which is used for friction texturing endless filaments, particularly manufactured filament material used as yarn. Yarn is drawn past a plurality of partially interleaved, overlapping, rotating friction discs, and the friction of the yarn against the discs imparts a false twist to the yarn as it is drawn past the discs. The discs are supported on a plurality of shafts arranged so that the discs overlap at one edge portion or area. For example, three such shafts are provided, preferably arranged in an equilateral triangular array. The invention is particularly concerned with damping the oscillations of the false-twisting unit and with maintaining the desired orientation of the unit whose oscillations are being damped.
A friction false-twisting unit is known from German Patent application DE-OS No. 29 36 845 in which bearings for the shafts, arranged in the support plate, are mounted with little radial oscillation by interposed rubber rings. In this way, absolutely quiet operation is assured, even upon high speeds of shaft rotation.
However, there are disadvantages. While the disturbances, which come, for instance, from the filaments or threads to be false-twisted or from the tangential drive belt for the shafts, are damped, nevertheless the relative axial positions of and the parallel relationship between the three shafts change for a short time, and this leads to yarn defects. Furthermore, close tolerances cannot be obtained between three shafts which are damped by rubber rings. Further still, the force of application of the tangential drive belt presses the individually driven, damped mount away to one side. This changes the geometry of the unit and thus also the quality of the yarn.